Recently there has been strong interest in processes of implicit memory among those who conduct research with humans. Implicit memory is commonly studied via the priming procedure, in which responding to a stimulus is affected by prior presentation of a related stimulus. A few recent studies have demonstrated the same sort of priming in nonhuman animals. The experiments in this proposal are designed to expand our knowledge about priming in a species of nonhuman animals (pigeons) in two ways. The first experiments are designed to test parametric aspects of priming in pigeons. These studies will examine the time course of the effects of priming over both relatively short and relatively long time intervals. Further, the research will examine how priming is affected by the degree of distortion of the prime and the target stimulus. The second aim of the research is to examine the possibility of conceptual priming in pigeons. Research with humans has indicated that priming can take place both when the prime is identical to the target, and when it is conceptually related to the target (i.e., from the same basic-level or superordinate class). The experiments described in the latter portion of this proposal will examine the possibility of conceptual priming in pigeons.